Tm hiu v in no (EEG)

Chng I: Khi nim? Tm quan trng? C

ch v cc SNG NO C BN?
1.in no l g?:
Electroencephalogram in no (EEG) lL phng php nghin cu
chc nng ca no da vo vic ghi li cc in th pht sinh trong t bo
no.
y l 1 th tc khng au, s dng a kim loi nh phng (in cc) gn
lin vi da u pht hin hot ng in trong no. Cc t bo no giao
tip thng qua cc xung in v hot ng tt c cc thi gian, ngay c khi
ang ng. Hot ng ny cho thy cc ng ln sng trn mt bn ghi
in no .
EEG l mt trong cc xt nghim chn on chnh ng kinh. in no
cng c th ng mt vai tr quan trng trong chn on cc ri lon no
b khc.



Lch s pht trin:
- 1791: Galvani cho thy c dng in sng trn ch
- 1848: Reymond dng in cc bng s loi tr dng in phn cc, t
chng minh rng c dng in tnh khi no ghi cng c
NC tip theo ca ng trn no ng vt(ch, ra, th) cng ging c v
thn kinh c kh nng pht sinh in5 v gi thit rng: trong mi m sng
u pht sinh dng in
- 1875: R.Carton l ngi u tin quan st hot ng in theo nhp ca no
ng vt
Dng sng no thu c ca ngi bnh khi ln cn ng kinh.
- H. Berger(1873-1941) ghi in no thnh cng ngi vo ngy 6/7/1924,
sau ng NC su hn v eeg sinh l v bnh l ngi
- Gibbs(1933) xut EEG lm sng l mt ngnh ring, lin quan cht ch
vi lm sng v m u cho nc ng kinh hoa k
- Cc NC su hn v : ng kinh(Lennox, Gibbs, Gastaut..), u
no(W.G.Walte)
- Cng vi s pht trin ca k thut hin i, k thut ghi EEG c ci tin,
t my u c 4 knh- 8-10-12-14-16-18-20-64.vi nhiu o trnh khc
nhau
- C nhiu phng php ghi: bt nhit, bt mc, vi tnh, video v hin i hn
ghi EEG vi monitor
-Ti Vit Nam: EEG c s dng nhiu ti cc bnh vin, phng khm
chuyn khoa v a khoa gp phn quan trng trong chn on v theo di
iu tr bnh nhn
- Ti BVTTTW EEG c t rt lu c s dng trong chn on ti phng
khm ngoi tr, gim nh y khoa, gim nh php y (bt buc).

2.Tm quan trng ca EEG trong lm sng:
- Mc d hin nay c nhiu phng php thm d chn on hin i nh
siu m, chp mch, CT scanner, MRI, chp pht tia positron(PET), nhng
EEG vn khng th thiu c trong nh gi khch quan v tin cy chc
nng ca no v ngy cng c ph bin rng ri trn ton th gii
- trc 1 tn thng thng c 3 kiu phn ng:
+c ch
+kch thch
+kch pht
- Khng c phn ng no l c trngtiu chun vng, c th do ri lon
chc nng hay thc tn
- Mt s eeg l kt qu ca tn thng, thng l hi phc, nhng cng c
th dng di chng, hay tin trin nng hn vi tin lng xu
- Cc phn ng nh, ri lon nh hi phc nhanh hn tn thng ln
- Cc bt thng eeg khng c trng cho bnh cn, cn nguyn khng th
suy ra t eeg m phi kt hp cc phng php khc
- Nghi ng c tn thng th eeg ch ra s c mt ca tn thng, s chu
ng ca no khi cc phng php khc cho du hiu m tnh: v d trong
chn thng s no- n ch ra ri lon, ng kinh hnh thnh
- Trong phng lc eeg c th cho thy loi cn, loi ng kinh, c bit mt
s ngi c eeg c ng kinh trong khi lm sng khng c cn, hoc cn
khng c trng hay n m gowers gi l ranh gii ca ng kinh
- Cc lot o lin tip vi khong thch hp c bit c li cho tin lng,
theo di iu tr gip nhiu cho phn bit tai bin mch no v ung th se xu
dn theo thi gian
- Nhiu tc gi trn th gii s dng EEG trong :
+ U no: Walter 1936
+ ng kinh : Gibbs, Jasper, Gastaut, Lennox 1936, Nguyn Mnh Hng
1981
+ Chn thng s no: Jasper
+Tm thn: Hill 1942, 1957
+Bnh l mch mu no: E.A.Zhimunskaja 1963
+ Trong gim nh kh nng lao ng, tuyn chn ngh nghip
+ NC tm sinh l v chn on chc nng
Eeg trong u no :
- Khi nghi ng c tn thng no m khng lm r c bng cc
phng php khc th EEG ch ra s c mt mt hay nhiu tn thng,
ngoi ra n cn ch ra mt cch khch quan s chu ng ca no khi cc
phng php khc cho kt qu (-)
- Tuy c nhiu phng php khc nhng do kinh t, do k thut nn khng
phi ai cng c iu kin o
- Trong u no: EEG c gi tr
+ Chn on sm
+ Chn on nh khu
+ c bit: nh gi tin lng v kt qu iu tr
+ Phn loi bnh l c u v l c s ngh cc phng php xt
nghim khc, trnh lng ph tin cho BN v BV do cc chi ph hin i
thng rt cao
EEG trong chn thng s no :
- Giai on cp: t ghi nhng cng c gi tr ty v tr v mc tn thng
+ Nh
+ Va
+ Nng
- Giai on xa sau chn thng: Quan trng hn
+ nh gi mc ri lon ca no
+ Gip nh gi chnh xc vng tn thng
+ c bit: Khi o c sng ng kinh c gi tr tin lng ng kinh di
chng v l tiu chun quan trng trong gim nh kh nng lao ng sau
ny, pht hin gi bnh, cho php hay khng lm mt s ngh trong iu
kin d tai nn
EEG trong bnh l mch mu no :
- Giai on cp: Ch yu da vo lm sng v cc XN CHA khc, EEG
khng th xc inh c c th loi bnh l mch mu no
+ Kh phn bit: u, p xe, mu t
+ C gi tr theo di tin lng
. Nng dn ln
.Nh dn
.Pht hin cc di chng mc d lm sng n nh
- Trong thiu mu mn tnh: Va x, thiu nng khng c hiu, ch c
tnh cht tham kho
EEG nhim c
EEG sa st tr tu
EEG hn m
EEG ng kinh: bi ring
EEG ri lon tm thn: bi ring
v ..v
# Hn ch ca EEG:

1. Cc ri lon tm thn, tm cn, CPTTT, thoi ha cht trng t ri
lon EEG, khng c hiu
2. Ch ghi da u nn ch kho st 1/3 dy ca no, vng su
khng kho st c. nu mun ch ghi c khi ng cc trung tm
su kim sot v no
3. Trong ng kinh in hnh c 10% EEG bnh thng
4. Kho st 100.000 bnh nhn tm c 47 ri lon c trng, mi ri
lon c tm 1 du hiu EEG c hiu, c du hiu l khc nh hay
ph nh mt triu chng bnh (xem ti liu hc tp EEG v lu huyt
no-BVTTTW2, 2007)

BNH Chn
on
Xcnh v
tr
Tin
lng
Theo
di q
Khc
ng
kinh
ng kinh + + + + +
U no + + - - +
Tai bin + + + + +
Lit no + + + + +
Suy gan + - + + -
Nhim c + - + + +
Thiu oxi no + + + + +
THEO DI IU
TR

Vim no + + + + +
Ri lon hnh vi - - - + +
CPTTT - - - + +
au u + - + + +

3.c ch v cc dng sng no c bn:
3.1 C ch:
Dng in xut pht t no ng nhin l khng mnh dch
chuyn kim ghi in no , nn c b khuych i (EEG amplifiers).
Mt khc cng cn c b lc (EEG filters) lc cc giao ng in xut
pht t tim, c v t mi trng bn ngoi. B lc ch cho php nhng
hot ng in c tn s trong mt khong gii hn (frequency range)
nh sn l c ghi nhn vo my in no, nhng hot ng in no
c tn s cao hn hoc thp hn khong gii hn , s b lc ra.
Trc khi ghi in no , cn thc hin vic o chun
(calibration) m bo l my s cho ng ghi chnh xc. Sng
ghi chun cung cp cho ta gi tr so snh bin cc sng in no.
Ngi ta dng mt xung in hnh ch nht, hnh tam gic, hay hnh
sin, c bin bit trc, a vo u vo ca b phng i ca my
ghi in no . Nh vy tn hiu chun s i vo tt c cc ng
ghi EEG, to ra mt sng chun trn bn ghi. Cn c vo sng chun
ny, ngi ta nh gi cc sng in no v mt bin .


3.2.Cc dng sng c bn:
Sng chun

3.2.1. Sng anpha(k hiu a)
a,Tnh cht
- Hnh sin, tn s 8 -12c/s, c 3 loi nhanh, chm, trung bnh
- V tr vng nh chm
- Ghi khi: Nhm mt, phng hi ti, khng qu nng hay lnh, khng suy
ngh
- Mt khi m mt: Phn ng berger(+)
b, ngha: Kt qu chui kch thch t bo thn kinh v no, anpha gn
vi s ngh ngi ca v no
c, Sng bnh l
- Mt i xng v tn s, bin 2 bn cu
- Mt phn ng nh sng
-Mt dng thoi, bin dng, kch pht anpha
3.2.2 Sng beta (k hiu b)
- Tn s 14 -35 c/s, bin thp <20 mn
- u th vng trc no: trn-trung tm
- Bnh thng n nh ty ngi, u th n
- ngha: nh gi s hng phn ca v no, tng khi cng thng, lo u
3.2.3. Nhp teta (k hiu q)
- Tn s 4 7c/s
- Ch yu tr em, ht khi 10 tui
- ngi trng thnh bnh thng khng c hay c tha tht, bin
thp
- Bnh l + Khu tr tn thng v no
+ Kch pht ng b cn xng 2 bn cu Tn thng di v
3.2.4. Nhp delta (k hiu )
- Tn s 0,5 3,5 c/s, bin thp <20 mn
- Ch yu tr nh, khi hn m, ng su sau 17 tui khng cn
- Ngi bnh thng khng c hay c v thp, t tha thi vng trc no
- Bnh l: Ch tnh trng thiu oxi no Tn thng thc th no
+ Kch pht delta 2 pha Tn thng cu trc di v
3.2.5. Mt s sng khc: nhp m, nhp ca s